Variable temperature measurements in cryogenic probe stations; forces on the probes
Lake Shore Cryotronics, US
Keywords: cryogenic probe stations, temperature measurements
Abstract:Electrical property measurements of nanoscale materials are important for characterization and understanding of materials and devices. Equally important is to measure these properties at various temperatures. We present results using a new probe design that allows the probe tips to remain in contact to sample during temperature changes. With this new design we demonstrate, with optical microscopy, the total tip movement of less than 2 microns when the temperature of the sample changes from 4.2K to 300K. The same probes that eliminate the movement from thermal expansion also improve the isolation of the measurements to external vibrations. Additionally, the forces on the probe are measured as the temperature changes. These measurements demonstrate that the probe design compensates for both movements of the probe arms as well as movements of the sample stage during the temperature change. . Typical noise levels in well designed measurements are 10 parts per million (rms) for resistance ranges from 1 ohm to 100K ohm.